... and we have a winner: gen3_mixed_blits reproduces the issue Daniel
Vetter originally found. It seems clear that we have some incoherence
between the RENDER and BLT units on gen3 that no amount of MI_FLUSH can
hide. Hmmm....
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
That little snippet creapt in and magically made render copy work -
by essentially disabling it.
Restore order, everything incoherent again.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>